New Surgical Heart Implant Could Save Kids From Multiple Surgeries

A new surgical heart implant might just be the solution to heart defects that affect millions of kids worldwide.

While medical implants have successfully saved the lives of millions of adults around the world, it has not produced the same results for children. Implants for kids have been complicated by the fact that these devices cannot expand in tune with the children’s growth. This is why a new surgical heart implant has been developed to address this problem.

Apparently, a team of researchers from the Boston Children’s Hospital and the Brigham and Women’s Hospital had developed a ‘growth-accommodating implant‘ for use in a cardiac surgical procedure called valve annuloplasty, according to the Science Daily. The method repairs any leaking mitral and tricuspid valves in the heart.

Currently, kids who have to undergo cardiac surgeries, such as the mitral and tricuspid valve repairs, have to go through multiple surgeries during their childhood to re-repair or replace leaking heart valves. Professor Pedro del Nido, Cardiac Surgery Chief at the Boston Children’s Hospital, said:

“Medical implants and devices are rarely designed with children in mind, and as a result, they almost never accommodate growth. So, we have created an environment here where individuals with expertise and interest in medical devices can come together and collaborate towards developing materials for pediatric surgery.”

With the new surgical heart implant, the number of heart surgeries needed by a child may decrease significantly since the implant is more durable and accommodates the child’s natural growth.

A new Surgical Heart Implant, a new Hope for Kids Suffering From Heart Ailments

In the study published by the researchers in the journal Nature, they wrote:

“Here, we report the design and use of a growth-accommodating device for pediatric applications that consists of a biodegradable core and a tubular braided sleeve, with inversely related sleeve length and diameter. The biodegradable core constrains the diameter of the sleeve, and gradual core degradation following implantation enables sleeve and overall device elongation to accommodate tissue growth.”

Aside from cardiac repair, it was also mentioned by the researchers that the said medical implant could be adapted for a variety of other growth-accommodating implants throughout the body.

“While the braided sleeve and polymer core work in concert to enable growth, they can be independently modified to achieve a range of device elongation profiles that apply to a broad spectrum of clinical applications. In addition to the pediatric cardiac and orthopedic surgeries already described, potential applications exist for oesophageal and intestinal atresias.

The braid could be engineered to have shape memory, such that as the polymer degrades after implantation in the esophagus or intestine the braid actively elongates to gradually increase the oesophageal or intestinal length. Another potential application is for the surgical treatment of mandibular condylar hyperplasia—a cause of asymmetric facial deformities in the case of unilateral condylar hyperplasia and prognathism (an underbite) in the case of bilateral mandibular condylar hyperplasia.”

The Development of the ‘Growth-Accommodating’ Surgical Implant

Professor del Nido’s team from BCH partnered with Jeff Karp, a Bioengineer and Principal Investigator at Brigham and Women’s Hospital, to develop the growth-accommodating implant. Karp’s expertise in chemical engineering and biopolymer materials was proven helpful to the research.

A. Commercially available fixed-size annuloplasty device used in adults. B. UHMWPE biaxially braided sleeve placed over a pre-curved cylindrical ESPGS polymer core. C. Biaxially braided sleeve pattern. D. Ex vivo demonstration of ring implantation with an en face view of the tricuspid valve. E. En face view of a freshly explanted tricuspid valve and ring 12 weeks after surgery. F. Cross-section through an explanted ring demonstrating the collagen layer that grew over the device (arrow). G. Explanted ESPGS samples demonstrate erosion at the polymer surface. H. Cross-sections through segments of the ring and annulus demonstrate regions of significant core erosion with ring thinning (top) and areas of less significant core erosion with less thinning of the ring (bottom). I. Tricuspid valve area at three study points: pre-implant, post-implant and euthanasia. J. A continuous-wave colour Doppler echocardiogram demonstrates only a trivial gradient (0.77 mmHg) across the tricuspid valve orifice (arrow) at the time of euthanasia, indicating that the growth-accommodating ring did not induce valve stenosis after implantation. RA. right atrium; RV, right ventricle. | Nature | nature.com

After reviewing numerous different concepts of the growth-accommodating implant, the team finally took their inspiration from the braided, expanding design of a Chinese finger trap, thus making their first proof-of-concept to be a tricuspid valve annuloplasty ring implant.

The implant design consisted of two primary components: a degrading, biopolymer core and a braided, tubular sleeve that elongates over time in response to the tensile forces exerted by the surrounding growing tissue, explained Eric Feins, co-first author of the paper and a fellow researcher from del Nido’s lab.

For the degrading core, Karp’s team recommended the usage of an extra-stiff, biocompatible polymer that begins to erode on its surface after the implantation.

“By adjusting the polymer’s composition, we can tune the core to degrade predictably over a pre-determined amount of time,” Karp explained.

“In combination with the braided sleeve exterior, this two-part implant concept could have many medical applications beyond the most obvious ones to enhance cardiac valve surgery in children,” del Nido said.

Right now, CryoLife, a biomedical device company is said to have started developing the concept of the growth-accommodating implant based on the data gathered from the in vivo experiment conducted by del Nido and Karp’s team.

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